Longships were sea vessels made and used by the Vikings from the Nordic countries for trade, commerce, exploration, and warfare during the Viking Age. The longship’s design evolved over many years, beginning in the Stone Age with the invention of the umiak and continuing up to the 9th century with the Nydam and Kvalsund ships. The longship appeared in its complete form between the 9th and 13th centuries. The character and appearance of these ships have been reflected in Scandinavian boat-building traditions until today.

The longship is characterized as a graceful, long, narrow, light, wooden boat with a shallow-draft hull designed for speed. The ship's shallow draft allowed navigation in waters only one metre deep and permitted beach landings, while its light weight enabled it to be carried over portages. Longships were also double-ended, the symmetrical bow and stern allowing the ship to reverse direction quickly without having to turn around; this trait proved particularly useful in northern latitudes where icebergs and sea ice posed hazards to navigation. Longships were fitted with oars along almost the entire length of the boat itself. Later versions sported a rectangular sail on a single mast which was used to replace or augment the effort of the rowers, particularly during long journeys.^{[citation needed]} The average speed of Viking ships varied from ship to ship but lay in the range of 5–10 knots and the maximum speed of a longship under favorable conditions was around 15 knots.

Harald Fairhair or Harald Finehair (Old Norse: Haraldr hárfagri, Norwegian: Harald Hårfagre), (c. 850 – c. 933), son of Halfdan the Black, was the first king (872–930) of Norway.

Little is known of the historical Harald. The only contemporary sources mentioning him are the two skaldic poems Haraldskvæði and Glymdrápa, which have been attributed to Þorbjörn Hornklofi or alternatively (in the case of the first poem) to Þjóðólfr of Hvinir. The first poem has only been preserved in fragments in 13th century Kings' sagas. It describes life at Harald's court, mentions that he took a Danish wife, and that he won a battle at Hafrsfjord. The second relates a series of battles Harald won. The validity of this evidence is doubtful and the facts offered by the poems are scant. Their unity is in any case questionable, as they have been reconstructed from fragments in the Kings' sagas, where they are attributed to more than one author.

Harald is not mentioned in any foreign sources earlier than the 12th century. His life is described in several of the Kings' sagas, but the first of these were not written until the end of the 12th century, over 250 years after his death. Their accounts of Harald and his life differ on several points, and much of the content is clearly mythological. He is credited with having unified Norway into one kingdom. Modern historians have generally assumed that his rule was limited to the coastal areas of southern Norway.